Preselection switch



June 18, 1957 M. L. GLOGAU 2,796,474

PRESELECTION SWITCH Filed June 6, 1955 5 Sheets-SheetI l INVENTOR 36 )W m"- MANFRED LLosAU AT TORNEY June 18, 1957 M. L.. GLOGAU 2,796,474

PRESELECTION SWITCH Filed June 6, 1955 5 Sheets-Sheet 2 INVENTOR MANFRED L.GL OGAU ATTORNEY June 18, 1957 M GLOGAU 2,796,474

PRESELECTION SWITCH Filed June 6, 1955 5 Sheets-Sheet 5 INVENTOR MANFRED .G| OGAU BY I 0MM WW ATTORNEY June 18, 1957 Filed June 6, 1955 M. L. GLOGAU PRESELECTION SWITCH 5 Sheets-Sheet 4 INVENTOR MANFRED L.. GLOGAU BY 1 MA WW AT TORNEY June 18, 1957 M. L GLoGAU 2,795,474

PREsELEcTIoN SWITCH Filed June 6, 1955 5 Sheets-Sheet 5 n rllllllI/,l Olla Il 48 INVENTOR MANFRED LAGLOGAU ATTORNEY United States Patent O PREsELEcrIoN SWITCH Manfred L. Glogau, Shorewood, Wis., assigner to Allen- Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Application .lune 6, 1955, Serial No. 513,467

13 Claims. (Cl. 200 17) This invention relates to certain features of preselection switches, that is to say rotary mlultiposition electrical switches of the type in which the switch may be preset from one to another of lits many alternative combinations of electrical contacts, with the current automatically turned-off during such presetting, and the circuits may then be energized and remain energized until the next presetting or until the current is otherwise turned off.

More particularly the present invention relates to certain features of preselection switches of the particular sort which have a control shaft capable of rotation to a plurality of selective positions, and of axial shift to a plurality of selective positions (preferably three). In such switches, there is usually spring rneans biasing the shaft to assume a mid axial position. One of the extreme axial positions, known as ythe stop position, :turns-off the current from some or all of the controlled circuits. This is the position in which it is usual to rotate the shaft to change the settings of :the switch. The shaft is then shifted to the other extreme axial position, known as the start position, which turns on the current. The mid position maintains the current either on or off, according which extreme axial position preceded it.

The inventive features, which will be hereinafter described, are especially but not necessarily adapted to be employed in multisection built-up switches, such as those portrayed in two prior patents of the present inventor, namely No. 2,319,503,V` issued May 18, 1945, and No. 2,438,970, issued Aprilj 6, 1948, to which two patents reference may be made for any collateral details not directly involved in the present invention.

In preselection switches of the general type to which the present invention is adapted, it is usually highly advisable that the switch-setting be not changed when the ycurrent is on. Accordingly Ithe principal object of the present invention is to provide means for automatically preventing rotation of the control-shaft except when in the stop position. For reasons (which include relieving the switch of torsional strains, and assuring that the stop positions coincide with the indexing positions) 'it is preferable that this means be located adjacent the controlhandle end of the shaft, and be combined or associated with certain other of the control mechanism, namely the star-wheel and associated spring-biased indexing roller, the main purpose of which elements are to assure that the rotation of the shaft will always come to rest at the center of one of its settings.

Also it is advisable in preselection switches for certain uses, to provide means either in addition to or in substitution for the rotation-preventing means, this additional or substituted means being for the purpose of limiting the rotation of the shaft to one direction only, when in at least one of its axial positions.

From all the foregoing it will b'e seen that the present invention more particularly resides in a rotary multiposition preselection electrical switch (preferably of modular construction) which lswitch includes: a main Patented June 18 1957 ICC frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective angular positions; means, preferably manually actuable, :located adjacent one end of the shaft, for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts carried by the main frame adjacent the shaft; a plurality of cams mounted on the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one cam mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; a detent carried by the main frame biased to engage :the indexing wheel to cause the shaft to come to rest in each of its selective angular positions; and one or both of the following kinds of stop means carried by the main frame for engaging the indexing wheel, namely: (1) stop means to prevent both clockwise and counterclockwise rotation of the shaft, when the shaft is in at least one (preferably two) of its axial positions (preferably its mid axial position and the position of the shifting and rotating means); and (2) stop means to prevent rotation of the shaft in one direction, but not in the other, when the shaft is in at least one of its axial positions; the indexing wheel, the detent, and the stop means being preferably located adjacent the shifting and rotating means.

The principal object of this present invention has already been stated earlier herein. That and other objects and advantages are readily evident from the foregoing general description of the invention, and/ or will appear in the .description to follow. In the description, reference is made to the accompanying drawings which form a part hereof, and in which thereare shown, by way of illustration but not of limitation, five specic forms in which this invention may be embodied.

In the drawings:

Fig. 1 is a side elevation of a switch, embodying the first variant of the present invention.

Fig. 2 is a top view of the same first variant.

Fig. 3 is a vertical longitudinal section of the same first variant, viewed as though cut along the line 3 3 of Fig. 2.

Fig. 4 is a right-hand end elevation of 4the same lrst variant, viewed from the line 4 4 of Fig. 3.

Fig. 5 is a vertical transverse section of Ithe same first variant, viewed `from the left as though cut along the line 5 5 of Fig. 3.

Fig. 6 is a vertical transverse section of the same first variant, viewed from the left as though cut along the line 6 6 of Fig. 3.

Fig. 7 is a vertical transverse section of the same first variant, viewed from the left as though cut along the line 7 7 of Fig. 3. It will be noted that the contact carriers and cam of Fig. 7, being actuable by axial movement, differ from those of Figs. 5 and 6, which are actuable by rotary motion.

Fig. 8 is a horizontal section of the left-hand portion of the same first variant, viewed as though cnt along the line 8 8 of Fig. 7.

Fig. 9 is the left-hand end elevation of the same first variant, viewed from the line 9 9 of Fig. 3.

Fig. l0 is a vertical transverse section of the same rst variant, viewed from the left as though cut along the line 10-10 of Fig. 3.

frame; a shaft; means mounting the shaft on the main l Fig. 1l is a vertical transverse section of the same first variant, viewed from the right as though cut along the line 11 11 of Fig. 3.

Fig. 12 is the top view of the left-hand portion of the second variant. This view corresponds to a portion of Fig. 2.

Fig. 13 is a vertical longitudinal section of the same portion of the second variant, viewed as though cut along the line 13-13 of Fig. 12. It corresponds to a portion of Fig. 3.

Fig. 14 is a vertical transverse section of the same second variant, viewed from the left as though cut along the line 14-14 of Fig. 13. It .corresponds to Fig. 10.

Fig. 15 is a vertical .transverse section of the same second variant, viewed from the right as though cut along the line 15-15 of Fig. 13. It corresponds to Fig. 11.

Fig. 16 is the top View of the third variant. It corresponds to a portion of Fig. 2, and to Fig. 12.

Fig. 17 is a vertical longitudinal section of the same portion of the third variant, viewed as though cut along the line 17 17 of Fig. 16. It corresponds to a portion of Fig. 3, and to Fig. 13.

Fig. 18 is a vertical transverse section of the same third variant, viewed from the left as though cut along the line 155-.-18 of Fig. 17. It corresponds to Figs. 10 and 14.

Fig. 19 is a vertical transverse section of the same third variant, viewed from the right as though cut along the line 19-19 of Fig. 17. It corresponds to Figs. 11 and 15.

Fig. 20 is the top view of the left-hand portion of the fourth variant, and illustrates the point of difference between the fourth variant and the first variant. Compare Fig. 2.

Fig. 21 is the top view of the left-hand portion of the fifth variant, and illustrates .the point of difference between the fifth variant vand Vthe first variant. Compare Fig. 2.

Throughout the description, the same reference-number is applied to the same member or to similar members.

Referring now to the drawings, more particularly to Figs. 1 to 11, and still more particularly Figs. 1 to 3, there will now be described the first variant of the present invention.

The case or housing for this switch is not shown.

Threaded bushing 31 extends leftwardly through a hole in front end-plate 32. A hexagonal flange 33, integral with this bushing, fits into a hexagonal recess surrounding this hole. A nut 34, screwed onto the threads of bushing 31 secures this bushing rigidly to pla-te 32.

In this bushing 31, there is mounted for axial shift and for rotation about its axis, a shaft 35. An operating handle 36 is secured to this shaft by a set-screw 37.

All of shaft 35, except a limited portion on its -lef-t-hand end is hexagonal in shape. The line of demarcation is clearly shown -in Fig. 3. Onto this hexagonal portion there can be slid a succession of interengaging camsleeves, made of insulating material. These sleeves are of two general sorts, 38 and 39, which will be more particularly described hereinafter.

The bore of these cam-sleeves has the configuration of a star made up of two superimposed hexagons. See Figs. 5, 6, and 7. This enables each sleeve to be secured on the shaft in any one of twelve selective angular positions, for purposes to be hereinafter explained.

At the left end of this succession of cam-sleeves there is a front collar 4.0, and at the right end there is a rear collar 41, the latter extending through a hole in rear end plate 42.

There is also an intermediate plate 43.

Adjacent each end of threaded bushing 31 in an annular groove in shaft 3,5, there is a C-washer 44, 45. These serve to limit the axial shifting of shaft 35 by contacting the espective ends of threaded bushing 31. C-washer 45 is located at the juncture of the cylindrical and hexagonal portions of shaft 35.

Against C-washer 45, and keyed to shaft 35 by having a hexagonal hole, there is a serrated indexing wheel 46, the functions of which play an important part in the present invention, as will be herein-after described.

Between this indexing wheel and front end collar 40,

and preferably not keyed to the shaft, there is spring-seat sleeve 47, having a constricted portion 47a on which two washers 48, 49, held apart by a spiral spring 5t), are free to slide. The unconstricted portion of this sleeve 47 projects through a hole in intermediate plate 43.

When shaft 35 is pulled to the left, the flange on the right-hand end of spring-seat sleeve 47 engages washer 49, pushing it to the left and thus compressing spring 50 against washer 4S, which is kept from moving by butting against intermediate plate 43. When the shaft 35 is pushed to the right, the shoulder on spring-seat sleeve 47 engages washer 48, pushing it to the right and thus compressing spring 50 -against washer 49, which is kept from moving by butting against adjacent segment 57. Thus the assemblage thus described constitutes means for biasing the shaft to assume and remain in its mid axial position.

At the rear (right) end of shaft 3 5, keyed thereto by a hexagonal hole, there is a rotation-stop washer 51, having a projecting finger 52. See Fig. 4. When the shaft is rotated, this finger contacts one or the other of two stops 53 (which can be screwed into any two of the twelve holes S4 in rear end plate 42), to limit the rotation of the shaft.

The F-slot at the bottom of plate 42 is to engage the head of a stud (not shown) in the switch housing to maintain the switch properly oriented with respect to the housing.

When indexing wheel 46, spring-seat sleeve 47, front end collar 40, one or more of cam sleeves 38, one or more of cam sleeves 39, rear end collar 41, and rotation stop washer 51 have al1 `been successively assembled on shaft 35, they are clamped together to the left against C-washer 45, by bolt 55 screwed into a hole in the rear end of the shaft, and thus forcing stop washer to the left.

Surrounding shaft 35 Aand the elements strung on it, as just explained above, between intermediate plate 43 and rear end plate 42 there are a succession of interlocking segments 57 of insulating material, preferably identical to simplify manufacture.

Between each pair of successive segments 57 there can be embraced and securely held by socketed engagement two Vstatiorlfiry Contacts 58 and two mountings 59 for movable contacts. See Figs. 5, 6 and 7. Herein the phrase pair of electrical contacts or pair of contacts will be used to signify two contacts which are brought together to close a circuit and are separated to break the circuit. The operation of the contacts will be explained hereinafter.

Front end-plate 32 and intermediate plate 43 are held apart by spacer sleeves 6.0 and by stand-off rivet k61 on plate 43. There is also a stand-off rivet 62 on plate 32, which serves to space the switch from thc switchhousing.

The main frame .of the switch, which consists of front endplate 32, spacer sleeves 60, segments 57, and rear end-plate 42, is held firmly together by two long screws 63, each of which extends from the rear through a lockwasher 64, and then through aligned holes in each of the above mentioned elements, end up in a threaded seat in front end-.plate 32. If desired each of these screws 63 can be bushed by'a long tube of insulating material 65, as shown in Figs. 5, 6, and 7.

Consider now, in conjunction with Fig. 2, Fig. 5. The particular cam-sleeve 39 of that section of the switch has cam-points 66. When shaft 35, carrying with it cam-sleeve 39, is rotated 30 clockwise, these points 66 engage transverse corrugation :67 of .contact-carrying; spring 68, forcing movable contacts 69 into electrical Contact with fixed contacts 58.

A similar result occurs in the switch-section shown in Fig. 6, when shaft 3S is rotated 30 counterclockwise.

The switch-section .of Figs. 7 and 8 is, however, considerably different. In this switchasection, springs 70 and "71 .correspond to springs .68 of the switch-sections of Figs. 5 and 6. But instead of the corrugations of springs 68, springs 70, and 71 carry conical points 72 and 73 respectively. And instead of the cam-points 66 of camsleeves 39, cam-sleeve 38 carries an annular boss 74. In the specific embodiment now under consideration, when shaft 35 is in its spring-biased mid-axial position, cone 73 has ridden up onto boss 74, thus forcing movable contact 76 into electrical contact with its fixed contact 58. But cone 72 is now toward the front of the switch from boss 74, and hence movable contact 75 is outl of touch with its fixed contact 58.

When handle 36 is pulled out (i. e. toward the observer in Fig. 7) cone 73 still remains up on boss 74, cone 72 rides up onto the boss. Thus both pairs of contacts are now closed. But when handle 36 is pushed in, cone 73 slides off boss 74. Thus both pairs of contacts are now open.

Each of stationary contacts 58, and each of mountings 59 for the movable contacts has a screw 77 for the attachment of electrical conduits.

A three-angular-position three-axial position threesection switch, having its contacts and cams arranged as just described is primarily adapted to the use, which is merely illustrative, namely to turn some reversible electric mechanism off and on.

The circuits for such use are well known in the art. See for example Fig. 14 of U. S. Patent No. 2,438,970 mentioned earlier herein. In connection withthe present showing, it is contemplated that the closing of the contacts of Fig. 5 by clockwise motion of handle 36 closes the circuits for forward motion of the actuated mechanism; and that the closing of contacts of Fig. 6 by counterclockwise motion of the handley closes the circuits for reverse motion of the actuated mechanism. But this is merely a presetting or preselection. For current to pass through either of the above circuits it is necessary that contacts 75 (normally open) be closed, in addition to contact 76 (normally closed) remaining closed. This is accomplished by pulling out on handle 36, as already described. The closing of both these contacts, in addition to activating the preset circuit, closes a solenoid-switch (not shown) which by-passes contact 75, so that when the handle snaps back into neutral, axially, the opening of contact 75 does not interrupt the current. When it is desired to stop the mechanism, the handle is pushed in, thus opening contact 76. This permits the solenoid switch to open, thus deenergizing all circuits until the handle is pulled out again.

The foregoing is just an example of one use of the switch of the present invention and being well-known'in the art is not illustrated.

There could be added many more segments and switchsections, similar to those of Figs. 5 and 6, each with one or two pairs of contacts. Cam points could be added, subtracted, and arranged at different angular positions about their cam-sleeves, all to suit almost any use to which a drum-switch could be put. As for the switchsection of Fig. 7, for some uses there might be only one pair of contacts; and, if it were desired to release one of the cones which ride upon annular boss 74 in some angular position or positions, a gap or gaps such as 74a could be provided in this boss. There could even be a plurality of sections like that of Fig. 7. As for the other sort of sections, as shown in Figs. 5 and 6, for some uses there might be only one pair of contacts. Many other changes or additions, similar to those just suggested, could be provided without departing from the present invention.

f It is desirable that there be means to automatically bias shaft 35 to come to rest in each of its twelve selective angular positions. This means is as follows. See Figs. l, 2, 3, 10, and l1. Serrated indexing wheel 46 has already been mentioned as secured to shaft 35, against rotation or axial movement with respect thereto. twelve peripheral indentations, preferably circular arcs.

This wheel has Pivoted on front end plate 32, as at 78, is a lever 79, which carries a detent in the form of indexing roller 80. This roller is long enough so that it engages wheel 46 in all axial positions of shaft 35, and preferably has the same or slightly larger radius of curvature as the indentations of wheel 46. Compression spring 81, interposed between lever 79 and a rearwardly bent ear 82 on front end plate 32, serves to press roller 80 against wheel 46, thus biasing the wheel to always come to rest at the mid point of each switch setting. The relative positions of the axis of wheel 46, pivot 78, and the axis of roller 80, are such that the roller opposes approximately equally, but does not prevent, the rotation of the wheel in each direction.

There is shown on intermediate plate 43 an ear 83 identical to ear 82, but this ear 83 serves no purpose except uniformity of manufacture of the two plates.

It is desirable to deactivate all circuits by pushing in on handle 36 before rotating it to change the presetting. To ensure this the following mechanism may be employed. See Figs. 1, 2, 3, l0, and 1l. A stop 83 is secured Ito the rear Iface of front end plate 32, as by screw 84. This stop is preferably cylindrical, of the same radius of curvature as the indentations of serrated indexing Wheel 46. It is long enough so as to engage the wheel 46 in all axial positions of shaft 35 except the rearmost. Thus it prevents rotation of the shaft, and hence prevents changing the presettings of the switch, except when handle 36 is pushed in.

Figs. 12 to l5 portray so much of a second variant of the invention as differs from the first variant thus far described.

In place of the fixed stop 83 of the first variant, which stop means prevented rotation in both directions in certain axial positions of `the shaft; there is provided in .the second variant stop means which prevents rotation of the shaft in only one direction in certain axial positions of the shaft.

This one-way stop means of the second variant is as follows. Pivdted on a pivot 85, which extends from front end plate 32 to intermediate plate 43, is a lever 86, which carries a movable stop or detent in the form of roller 87. rDhis roller as shown is just long enough to engage serrated indexing wheel 46 in all #axial positions of shaft 35 except the rearmost position, and preferably has the same radius of curvature as the indentations of wheel 46. A helical spring 88, wrapped around pivot 85, has its ends extended tangentially, respectively to engage an annular groove 89 in adjacent spacer sleeve 60, and to tit between roller 87 and the head of pivot 90 which secures roller 87 pivotally to lever 86.

For uniformity of manufacture, itt is convenient to have all spacer sleeves 60 possess this groove 89, even when not used in conjunction with spring 88.

Lever 86 is positioned on its shaft 85 between a washer 91 and a sleeve 92. The spring 88 is positioned on sleeve 92 between the lever and a washer 93. And all is held in place by a C-washer 94 in an annular groove on shaft 85. Note also the angled end 95 of lever 86, which by contacting plate 43 serves to maintain roller 87 properly spaced axially.

The relative positions of the axis of wheel 46, pivot 85, and pivot 90 are such that the rotation of serrated wheel 46 counter-clockwise as seen in Fig. 14 (clockwise in Fig. 15) forces roller 87 toward, nather than away from the wheel, thus locking the wheel against rotation; but the mechanism just described does not prevent rotation of the wheel in the opposite direction.

Due to the limited rearward extension of roller S7, already mentioned, this one-way prevention of rotation does not function when the handle is pushed in. Thus, with the circuits activated, the switch can be set only by rotation in one direction, but it can be preset by rotation n either direction.

The stop mechanism just described could, with the A7 indexing mechanism omitted, perform also the indexing function, except in the pushed in position.

Figs. 16 to 19 portray so much of a third variant as necessary to illustrate how this Ithird variant combines the distinguishing features of the other two. Thus it will be noted that this third variant retains the indexing mechanism of the other two, .and combines the positive stop means. of the first variant with the one-way stop means of the second variant. As shown, lever 86a differs from corresponding lever 86 by being shorter. Roller 87a differs from corresponding roller S7 by being longer, thus functioning to limit rotation to one direction in all axial positions. And spring 88 bears against roller 37a, instead of between roller 87 and the head of its pivot 9i) as in the second variant.

In the third variant, roller 87a could perform the indexing function in all axial positions, if the centering mechanism were omitted, but the presence of both mechanisms is preferred. y

Fig. 20 illustrates Ihow xed stop 83 of the first and third variants, which stop extends so far and only so far rearwardly as to prevent shaft-rotation in the pulledout and mid axial positions, but not in the pushed-in position, can be modified into longer fixed stop 83a, with annular groove 96a, thus permitting shaft rotation only in mid axial position.

Fig. 21 similarly illustrates how this fixed stop can be modified into fixed stop 83b with a differently located annular groove 9615, thus permitting shaft rotation only in pulled-out position.

Now that five embodiments of the invention have been shown and described, and several variations therefrom have been suggested,` it is to be understood that the invention is not to be limited to the specific forms or arrangements `of parts herein shown and described.

By virtue of the modular construction of the segments, and contacts, and contact-carrying Springs, and Camslceves; and by further virtue of the varying forms, and pos-sible permutations and combinations olf the indexing means, the fixed-stop means and the one-way stop means, associated with indexing wheel 46; the switch of the present invention is readily adaptable to practically every use for which a drum-switch could be designed.

What is claimed is:

l. In a rotary multiposition preselection electrical switch, the combination comprising: a main frame; a shaft; means mounting the shaft on the main frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective angular positions; means for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts, carried by the main frame adjacent the shaft; a plurality of cams mounted on and rotatable with the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one cam mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; a detent carried by the main frame for engaging successive serrations of the indexing wheel to bias the shaft to corne to rest in each of its selective angular positions; and stop means carried by the main frame for engaging serrations of the indexing wheel to prevent rotation thereof, and hence of the shaft, in at least one direction, in at least one of the axial positions of the shaft.

2. A switch according to claim l, wherein the means for axially shifting and rotating the shaft is manually operable and is located adjacent one end of the shaft, and wherein the indexing wheel, the detent, andthe stop means are located adjacent that end of the shaft which is adjacent the manual means.

3. A switch according to claim l, wherein there is spring means for biasing the detent to bear against the indexing wheel.

4. In a rotary multiposition preselection. electrical switch, the combination comprising: a main frame; a shaft; means mounting the shaft on the main frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective angular positions; means for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts, carried by the main frame adjacent the shaft; a plurality of cams mounted on and rotatable with the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one cam mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; a detent carried by the main frame for engaging successive serrations of the indexing wheel to bias the shaft to come to rest in each of its selective angular positions; and stop means carried by the main frame for engaging the indexing wheel to prevent rotation thereof, and hence of the shaft, in at least one of the axial positions of the shaft; wherein the stop means prevents rotation in only one direction.

5. A switch according to claim 4, wherein the stop means prevents such rotation in all axial positions of the shaft.

6. In a rotary multiposition preselection electrical switch, the combination comprising: a main frame; a shaft; means mounting the shaft on the main frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective angular positions; means for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts, carried by the main frame adjacent the shaft; a plurality of cams mounted on and rotatable with the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one cam mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; a detent carried by the main frame for engaging successive serrations of the indexing wheel to bias the shaft to come to rest in each of its selective angular positions; and stop means carried by the main frame for engaging the indexing wheel to prevent rotation thereof, and hence of the shaft, in atleast one of the axial positions of the shaft; wherein the stop means prevents both clockwise and counterclockwise rotation; and wherein there is also stop means carried by the main frame for engaging the indexing wheel, to prevent rotation thereof, and hence of the shaft, in only one direction, in at least some of the axial positions thereof.

7. In a rotary multiposition preselection electrical switch, the combination comprising: a main frame; a shaft; means mounting the shaft on the main frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective angular positions; means for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts, carried by the main frame adjacent the shaft; a plurality of cams mounted on and rotatable with the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one cam mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; a detent carried by the main frame for engaging successive serrations of the indexing wheel to bias the shaft to corne to rest in each of its selective angular positions; and stop means carried by the main frame for engaging the indexing wheel to prevent rotation thereof, and hence of the shaft, in at least one of the axial positions of the shaft; wherein there are three selective axial positions of the shaft, and wherein the stop means prevents both clockwise and counterclockwise rotation, but does this in only two of the three axial positions.

8. A switch according to claim 7, wherein the stop means prevents rotation in the mid axial position and in one of the extreme axial positions.

9. A switch according to claim 8, wherein there is spring means for biasing the shaft to assume and remain in its mid axial position.

10. A switch according to claim 9, wherein the means for axially shifting and rotating the shaft is manually operable and is located adjacent one end of the shaft, and wherein the stop means prevents rotation when the shaft is axially shifted in the direction towards the manual means.

1l. In a rotary multiposition preselection electrical switch, the combination comprising: a main frame; a shaft; means mounting the shaft on the main frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective an gular positions; means for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts, carried by the main frame adjacent the shaft; a plurality of cams mounted on and rotatable with the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one ca-m mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; a detent carried by the main frame for engaging successive serrations of the indexing wheel to bias the shaft to come to rest in each of its selective angular positions; and stop means carried by the main frame for engaging the indexing wheel to prevent rotation thereof, and hence of the shaft, in at least one of the axial positions of the shaft; wherein the stop means prevents rotation in at least one direction; and wherein there are three selective axial positions of the shaft, and wherein there is spring means for biasing the shaft to assume and remain in its mid axial position.

l2. In a rotary multiposition preselection electrical switch, the combination comprising: a main frame; a shaft means mounting the shaft on the main frame for axial shift into a plurality of selective positions, and for rotation about its axis into a plurality of selective angular positions; means for axially shifting and rotating the shaft; a plurality of pairs of electrical contacts, carried by the main frame adjacent the shaft; a plurality of cams mounted on and rotatable with the shaft for causing respective pairs of contacts to open and close, responsive to various angular positions of the shaft; at least one cam mounted on the shaft, for causing at least one corresponding pair of contacts to open and close, responsive to various axial positions of the shaft; a serrated indexing wheel, carried by the shaft for rotation and axial shift therewith; and means comprising a lever pivoted on the main frame, a detent carried by the lever for engaging successive serrations of the indexing wheel, and a spring carried by the main frame biasing the detent to so engage the serrations, these means being for biasing the shaft to come to rest in each of its selective angular positions, and being so relatively placed that rotating the shaft in one direction will lock the shaft against further rotation in that direction.

13. A switch according to claim l, wherein there are three selective axial positions of the shaft; and wherein the stop is effective in only two of these three positions.

References Cited in the file of this patent UNITED STATES PATENTS 

